doi:10.16186/j.cnki.1673-9787.2020.2.9

Received:2019/06/15

Revised:2019/07/30

Published:2020/03/15

Study on the extraction and separation of rare earth elements yttrium from theleaching of coal fly ash

JI Wanshun1, ZHOU Changchun1,2, PAN Jinhe1, CAO Shanshan1, TANG Mengcheng1, HU Tingting1

1.School of Chemical Engineering and Technology， China University qfMining and Technology， Xuzhou  221116 ， Jiangsu， China;2.Key Laboratory of Coal Processing and Efficient Utilization， Xuzhou  221116 ， Jiangsu， China

Abstract:To extract and separate the rare earth element of yttrium from the coal fly ash leaching liquid， the synergistic extraction system was used to study the coal fly ash leaching liquid. In this paper， the pure yttrium oxide leaching solution was taken as the research object. To explore the optimal parameters in the extraction process， two extractants di-2-ethylhexyl phosphonic acid （ P204 ） and 2-ethylhexyl phosphonic acid mono-2-eth- ylhexyl ester （ P507 ） were used to the synergistic extraction of yttrium in the single rare earth element yttrium oxide leaching solution. Results found that when the volume ratio of two kinds of extractant P204： P507 was 3：7 ， extraction total volume concentration was 10% vol. ， oil-water ratio was 1. 33 （ O/A =1.33 ） ， the contact time was 30 minutes， solution pH was 1.4 ， the temperature was 25 ℃，yttrium extraction efficiency can reach 89% ， the maximum value of synergistic extraction coefficient R was 1.7 ， which showed that two kinds of extractant had good positive synergistic effects. Based on the above experiments， the optimal conditions were applied to the extraction of yttrium from coal fly ash leaching liquid. The results showed that the yttrium （ Y） and lanthanum （ La ）， cerium （ Ce ）， praseodymium （ Pr ）， neodymium （ Nd ） separation factor β_Y，La，β_Y，Ce，β_Y，Pr，β_Y，Nd coefficient were 222. 82，142. 82，146. 97，119. 81 under the synergistic extraction system， which were higher than separation factor of P204 ， P507 single extraction system. It showed that synergistic extraction system could separate yttrium from other rare earth elements and provide theoretical guidance for industrial separation of rare earth elements. By using the constant molar method and slope method， the structure of the complex of P204 and P507 synergistic extraction of rare earth element yttrium was inferred， and the extraction mechanism equation was determined.

Key words:yttrium;extractnt;synergistic extraction;leaching of coal fly ash;mechanism of extraction process

粉煤灰浸出液中稀土元素钇的萃取分离研究_吉万顺.pdf